Machine for stretching nylon thread



Jan. 17, 1956 M. cuRRY MACHINE FOR STRETCHING NYLON THREAD 5 Sheets-Sheet l Filed Oct. 5. 1950 IN V EN TOR.`

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HTTOS/Vfy Jan. 17, 1956 M. cuRRY MACHINE FOR STRETCHING NYLON THREAD 5 Sheets-Sheat 2 Filed Oct. 5, 1950 Jan. 17, 1956 M. CURRY MACHINE FOR STRETCHING NYLON THREAD 5 Sheets-Sheet 3 Filed Oct. 5, 1950 Jan. 17, 1956 M. cURRY MACHINE FOR STRETCHING NYLON THREAD 5 Sheets-Sheet 4 Filed Oct. 5, 1950 le/6 W Jan. 17, 1956 M. CURRY MACHINE FOR STRETCHING NYLON THREAD 5 Sheets-Sheet 5 Filed oct. 5. 195o 1N V EN TOR.

nited States Patent O t MACHINE FOR STRETCHING NYLON THREAD Malcolm Curry, Flanders, N. J., assigner to The American Thread Company, New York, N. Y., a corporation of New Jersey Application October 5, 1950, Serial No. 188,543

4 Claims. (Cl. 223-62) The present invention relates to machines for stretching nylon thread.

For certain purposes, particularly for the use of nylon thread in sewing machines, it is has been desirable that its normal elongation at breaking point, usually in the neighborhood of 25 to 30 percent be reduced to such a percentage, in the neighborhood of 12.5 to 18 percent as will not produce undue puckering of the fabrics being sewn. Excessive elongation may in some instances also cause the nylon sewing thread to contract and draw into the fabrics the ends of stitching, thus reducing the effectiveness thereof to the extreme edges of the fabrics.

It has also been found that by the stretching of nylon threads under conditions of high temperature, in the neighborhood of 425 degrees F. but under 482 degrees F., the approximate melting point of nylon, the ultimate or permanent elongation can be reduced from that of normal nylon, and that in this process of heat stretching, the twist of the thread becomes set and tends to remain in such set condition.

One of the objects of the present invention is to provide a machine for thus reducing the stretch in nylon thread, which is of simple and cheap construction, requires a minimum amount of labor to operate, and is capable of operating at high speed.

The several features of the invention, whereby these and other objects may be attained, will be readily understood from the following description and accompanying drawings, in which:

Figure l is a side elevation, partly in section, of the main portion of the machine;

Fig. 2 is a detail sectional elevation, on an enlarged scale, taken substantially on the line 2-2 of Fig. 3;

Fig. 3 is a plan view of the portion of the machine shown in Fig. l;

Fig. 4 is a rear end view, on an enlarged scale, and partly broken away, of the machine;

Fig. 5 is a sectional view, on an enlarged scale taken substantially on the line 5--5 of Fig. l;

Fig. 6 is a sectional elevation, on an enlarged scale, taken on the line 6-6 of Fig. l and Fig. 7 is a view corresponding to Fig. 6, but with certain parts shown in a different position.

The threads to be treated may be supplied to the machine from a supply creel of conventional form (not shown).

From the creel, the individual threads 2 pass through porcelain thread guides 4 which are mounted on a guideboard 6. The guides 4 cause the threads to be arranged side by side in close proximity.

From the guides 4, the web of threads thus formed pass over a pair of nip rollers 8 and beneath an upper nip or pressure roll 10. T he web then passes beneath a guide rod or roller 12, from which it passes over the under side of a longitudinally extending convexedly curved heating plate 14 of a heater 16. From this heater the web passes beneath a guide-rod or roller 18 and over rifice a cooling roller 20. The threads of the web then pass through thread guides 22 mounted on a guide-board 24, between lower nip rollers 26 and an 'upper nip roller 28 and then through stationary thread-guides 30 mounted on a stationary guide-board 31 on the machine frame. For the purpose of winding on spools or bobbins, the threads then pass to a take-up of the type usually employed for quilling or like processes.

Each of the guide-boards 6 and 24 which respectively carry the thread-guides 4 and 22 is supported at one end by and pivotally connected with the upper end of a link 32 which has its lower end pivoted on a bracket 34 of the machine frame, and has its other end supported by and pivotally connected with the upper end of a lever 36 which is pivoted on a bracket 38 on the machine frame, and carries on its lower end a cam roll 40 which engages a cam 42. The two cams 42 are secured on a shaft 44 which is journaled in bearings on the machine frame, and is driven through Worm gears 46 and 47 by a shaft 48. This shaft 43 is journaled on the machine frame and is driven by a sprocket chain 50 which passes over a sprocket wheel on said shaft, and a sprocket wheel on the drive shaft 52 of the machine.

With this construction the guide-boards 6 and 24 and the thread guides supported thereby are reciprocated in a direction transversely of the machine. The length of the reciprocating movement is substantially threefourths of an inch, and when the machine is operated at a thread speed of 300 feet per minute, there may be substantially live reciprocations per minute.

The nip rollers of each pair 8 and 26 have projecting stud shafts 54 at their ends which are journaled in bearings on the machine frame. The shafts S4 at one end of the pair of nip rolls 3, and the shafts at the opposite end of nip rolls 26 carry gears 55 which are operatively engaged by a gear 56 so as to drive the nip rolls, each gear 56 being secured on a shaft 57.

Each gear 56 is driven through a sprocket chain 58 which passes over a sprocket wheel on the shaft 57 of the gear, and a sprocket wheel on the drive shaft 52. The nip rolls 26, however, are driven at a greater speed than the nip rolls 8, and the relative speeds of the two sets of rolls may be varied by changing the size of the gear 56 which drives the rolls 26.

Each of the upper nip rolls 10 and 28 has its ends journaled in the outer ends of the arms of levers 62 pivotally mounted on brackets on the machine frame, the other arms of the levers being provided with adjustable balance weights 64. By adjusting the weights 64 the pressure applied by the upper nip rollers 10 and 28 on the web of threads may be varied as desired.

The guide rods or rollers 12 are mounted on arms 66 which may be adjusted to vary the vertical positions of the rollers, and thus vary the points where the threads come into contact with and leave the curved heating plate 14.

As shown, the heater 16 is secured on the underside of bracket arms 68, which have downwardly extending arms at one end that are pivotally mounted on pins 70 on brackets 72 secured on a side frame of the machine. The other ends of the bracket arms 68 engage the upper ends of uprights 74 on a side frame of the machine when the heater is in its normal horizontal position, and are held in this position by engagement of the upper ends of latch members 76 with lugs 78 on the arms 68. The latch members 76 are adapted to release the arms 68 by means of a chain 77 connecting the lower ends of the latch members, and provided with an operating handle 79. When the latch members are released by forcing the handle 79 downwardly, the arms 68 and consequently the heater 16 are swung upwardly about the pivot 70 outpf contact with the thread by means of counterweights r8.7 hereinafter described. The arms .68 and .the heater 16 may be then swung to their uppermost position by means of a handle 80 which is in the form of a rod connecting vthe ends fof :said farms 68.

When the farms 168 fand .the heater 16 are ithus Aswung upwardly, they may .be held .in their raised position by means of levers .82 'which `are .pivoted .on .pins :84, and have .the rends of .corresponding arms thereof provided with elongated :slot-s 86 through which a 'pin 88 connecting the depending portions :of the arms :63 extends. The other arms of the levers 82 are provided with .the counterkweights :8.7 above referred to, 'and a connecting pin B9, .whereby when the bracket arms #.68 .and zthe heater .16 ,reach their raised position, .the --pin :89 snaps :over a :spring actuated detent 90 so as to hold the heater .in position. The '.detent 199 is pivotally mounted =on a `bracket ron a side .frame of fthe machine and is held in latched position Eby a .spring 91. To release the `detent from the .pin

89, :a '.chain tor cond has Aone :end lconnected ythere-with and its other end `extended through :a `clip on the other side frame. A knob 93 is secured to this end of the chain wherebyl upon pulling on the chain by means of the knob the .detcnt 9.0 .may be released 'from the pin '89, allowing the heater tto be restored 'to its normalposition and .held in position lby the latches 76.

The roll is mounted to turn .freely and its lower portion extends into a pan of cooling water. The main drive shaft A5.2 is driven from a motor shaft 94 through a `belt 95 that passes over pulleys -on the shafts S2 and 94.

A doctor blade 96 is associated with each nip roll of eachset 8 and 10 .and 26 and 28, the doctor blade being in advance of the area of normal contact of the threads with the rolls.

The web may contain as many as 100 or more threads, and it is important that Ithe individual threads be held firmly in the bite of the nip rolls of the two sets. To .effect this, all of the rolls, both the driven rolls 8 and 26, and the pressure rolls 10 and 28 should be nicely balanced, carefully ground and polished, and given a finish coat of chromium plating to reduce wear to a minimum. It is also highly important that the three nip rolls of each set be very accurately alined in parallel with each other to insure the bite `of the rolls being as evenly distributed as possible on the several threads of the web in order to produce even and uniform stretch on all of the threads.

It has been found desirable that the length of thread in contact with the convex heating plate 14 be altered to suit the size of the threads being treated, the temperature of the heated surface, and the linear speed of the threads .against the heater. This may be effected by raising and lowering the adjustable guide rods or rollers 12 and 18 at the ends of the heating plate 14. The amount of this thread contact is determined by experience and the resulting residual stretch desired. The heater 16 may be of the electric resistance type and automatically controlled by means of a thermostat; and control swtiches (not shown) to turn the current on or olf as desired.

It has also been found in commercial operation that with the machine running at approximate thread speed of 300 feet per minute and adjusted to effect about l() percent theoretical stretch, the individual threads may occasionally break or piecing knots in the nylon supply bobbins or cones may pull out due to the `high tension exerted upon the thread, resulting at times in a tendency for the loose ends to wrap up on the various rolls, thus decreasing the desired bite upon the threads in the nip roll sets. To overcome this, the doctor blades 96 which are preferably made of relatively soft plastic material, are so placed as to peel olf the rolls the discontinuous ends before they have an opportunity to encircle and build up' on the rolls.

The ends so peeled off drop harmlessly tothe floor where they can be easily observed by the machine oper- .ator .who .in practice .breaks the particular ends out of the web behind the driven lnip roll 8 while the machine is in operation, thus allowing the other threads of the web to continue on in the stretching operation with a minimum of interruption. This practice of breaking out ends and keeping the stretching .unit and majority of the threads in continuous motion has been found to yield substantially greater machine hour output than would result in the stoppage for piecing 'of each broken for unknotted end.

When the number of broken out ends become sufficient, say l0 percent of the total, to warrant stopping the machine to piece out `these ends again through 'the machine, upon stopping the machine the operator simultaneously pulls the handle 79 to release the latches 76 whereupon the heater 16 rises by virtue of the counterweights 87 out of Contact with the web of thread so as to prevent them from becoming unduly heated, or by being too llong in contact with the heating plate 14.

In practice, in starting up the machinejthe 4guide rods 12 and 18 are yfirst dropped to :such position as to insure the .threads not contacting the Vheating plate 1:'4 when the heater is lowered into its down or operating position. After the heater is thus lowered and latch'ed, the machine and the take-up quiller are started in loperation simultaneously, and the guide :rods 12 :and 18 are then raised to such a position 'as to .make the desired amount of vcontact lbetween kthe :heater and *the web necessary to produce the .amount Aof heat in the nylon required to permit it being stretched and heat set to the degree best suited to the end `use of the `nylon thread.

The degree of stretch of the nylon thread may be varied as desired by varying the degree of 'differential surface speed between the two sets of nip rolls Sand 10, `and .26 and 28. This may be easily accomplished by making suitable gear changes in the drive of the rolls.

The amount of theoretical stretch and, therefore, the size of the gears employed is rdetermined by the desired amount of residual stretch at breaking load Afor 'the particular end use t-o which the stretched and heat set nylon is to be put. This residual stretch may vary in .line thread of say, denier, from about 12.5 to 20 percent. l

It will be lnoted that the stretch in the 'thread occurs principally as the thread passes in .intimate rconta-ct with the underside of the curved heating plate 14 to the 'cooling roll 20, where the thread is quickly cooled and the stretch is substantially set.

Oscillation of the guide boards 6 and 24 back and forth a slight amount across and at right angles to the main axis of the machine as above described, serves to prevent the nylon thread from following fixed paths ycontinuously and thus cutting grooves in parts of the machine, and also tends to prevent undue flattening of the nylon threads.

While my improved method and machine is particularly adapted for use in treating nylon, they may be employed in treating other synthetic fibers of thermo-plastic type, and it is to be understood that the term nylon as used in the claims shall be construed to include such other fibers,

WhatI claim is:

l. In a machine for 'treating nylon threads, means for feeding the threads longitudinally in a web with the threads arranged parallel and spaced apart in close proximity comprising two sets of feed rolls for the web, and` two series of thread guides for the web respectively arranged in advance of said two sets of feed Vrolls through which the threads pass, a longitudinally curved `heating plate positioned between the two sets of rolls in-contactwith which the web of threads pass so as to heat the threads slightly below the melting point of .the nylon, means for driving the rolls of the two sets .at different speeds so as to stretch the threads a predetermined degree, and means for relatively adjusting the heating plate and the path of travel ofthe web so as to vary the length of contact between the threads and the heating plate.

2. A construction according to clam'l in which' each series of thread guides is mounted on a guide-board eX- tending transversely of the machine, and means is provided for oscillating said boards transversely of the machine to cause the web of threads to be moved transversely thereof.

3. In a machine for treating nylon threads, means for feeding the threads longitudinally in a web with the threads arranged parallel and spaced apart in close proxi mity comprising two sets of feed rolls for the web, each set of feed rolls comprising two rolls horizontally arranged and spaced apart over the upper portions of the peripheral surfaces of which the thread passes, a pressure roll for applying pressure to the thread as it passes over said two lower rolls, and means for driving the two sets of feed rolls to eifect feeding of the threads, a longitudinally curved heating plate positioned between the two sets of feed rolls in contact with which the web of threads passes so as to heat the threads slightly below the melting point of the nylon, means for driving the two lower rolls of the two sets at different speeds, and means for varying the path of travel of the web with relation to the heating plate to vary the length of contact between the threads and the heating plate.

4. In a machine for treating nylon threads, means for feeding the threads longitudinally of the web with the threads arranged parallel and spaced apart in close proximity comprising two s-:ts of feed rolls for the web, a longitudinally curved heating plate positioned between the two sets of rolls in contact with which the web of threads passes so as to heat the threads slightly below the melting point of the nylon, means for driving the rolls of the two sets at different speeds, and guide rods arranged adjacent the ends of the heating plate adapted to be vertically adjusted so as to vary the length of contact between the'threads and the heating plate.

References Cited in the file of this patent UNITED STATES PATENTS 51,471 Mclnroy Dec. 12, 1865 771,136 Fredenburgh Sept. 27, 1904 800,270 Couche Sept. 26, 1905 2,075,156 Albero Mar. 30, 1937 2,199,411 Lewis May 7, 1940 2,400,325 Winslow May 14, 1946 2,624,934 Munson et al Jan. 13, 1953 

1. IN A MACHINE FOR TREATING NYLON THREADS, MEANS FOR FEEDING THE THREADS LONGITUDINALLY IN A WEB WITH THE THREADS ARRANGED PARALLEL AND SPACED APART IN CLOSE PROXIMITY COMPRISING TWO SETS OF FEED ROLLS FOR THE WEB, AND TWO SERIES OF THREAD GUIDES FOR THE WEB RESPECTIVELY ARRANGED IN ADVANCE OF SAID TWO SETS OF FEED ROLLS THROUGH WHICH THE THREADS PASS, A LONGITUDINALLY CURVED HEATING PLATE POSITIONED BETWEEN THE TWO SETS OF ROLLS IN CONTACT WITH WHICH THE WEB OF THREADS PASS SO AS TO HEAT THE THREADS SLIGHTLY BELOW THE MELTING POINT OF THE NYLON, MEANS FOR DRIVING THE ROLLS OF THE TWO SETS AT DIFFERENT SPEEDS SO AS TO STRETCH THE THREADS A PREDETERMINED DEGREE, AND MEANS FOR RELATIVELY ADJUSTING THE HEATING PLATE AND THE PATH OF TRAVEL OF THE WEB SO AS TO VARY THE LENGTH OF CONTACT BETWEEN THE THREADS AND THE HEATING PLATE. 